Heat transfer wheels which provide directionally oriented air passages are commonly constructed of spirally wound, interleaved, flat and corrugated metal strips. These strips are wound around a hub and are capped at their outer circumference by a generally cylindrical rim. Such wheels can be relatively large in diameter, for example 12 feet, and are mounted to rotate through hot and cold air passages whereby the interleaved strips can provide a medium for transferring heat from the hot air passages to the cold air passage. This type of heat transfer wheel is a conventional construction and arrangement.
Among the problems encountered with these types of heat transfer wheels is the tendency of the concentric layers of interleaved strips to telescope in an axial direction, and also, when rotating in a vertical plane, the medium has a tendency to alternately compress against the hub and the outer rim during rotation through each 360.degree. turn.
The prior art has addressed these problems and some examples of proposed solutions can be found in U.S. Pat. Nos. 3,702,156, 3,290,764, 2,887,456 and 2,579,912, and French Pat. No. 1,285,255.